diff --git a/autotest/t034_test.py b/autotest/t034_test.py
index 2b30612263..cd32013b56 100644
--- a/autotest/t034_test.py
+++ b/autotest/t034_test.py
@@ -622,6 +622,38 @@ def test_load_write_wel_option_line():
     assert wel.iunitramp == 20
 
 
+def test_uzf_negative_iuzfopt():
+    model_ws = f"{base_dir}_test_uzf_negative_iuzfopt"
+    test_setup = FlopyTestSetup(verbose=True, test_dirs=model_ws)
+
+    ml = flopy.modflow.Modflow(
+        version="mfnwt",
+        exe_name="mfnwt.exe",
+        model_ws=model_ws
+    )
+    dis = flopy.modflow.ModflowDis(
+        ml,
+        nper=2,
+        perlen=[1,1],
+        nstp=[1,1],
+        tsmult=1,
+        steady=[True, False]
+    )
+    bas = flopy.modflow.ModflowBas(ml)
+    upw = flopy.modflow.ModflowUpw(ml)
+    oc = flopy.modflow.ModflowOc(ml)
+
+    uzf = flopy.modflow.ModflowUzf1(
+        ml,
+        nuztop=3,
+        iuzfopt=-1,
+        irunflg=1,
+        ietflg=1,
+        irunbnd=1,
+        specifysurfk=True,
+        seepsurfk=True
+    )
+
 if __name__ == "__main__":
     test_create_uzf()
     test_read_write_nwt_options()
@@ -632,3 +664,4 @@ def test_load_write_wel_option_line():
     test_load_write_wel_option_block()
     test_load_write_wel_option_line()
     test_uzf_surfk()
+    test_uzf_negative_iuzfopt()
diff --git a/flopy/modflow/mfuzf1.py b/flopy/modflow/mfuzf1.py
index 7f3b469a93..3e3ca31d70 100644
--- a/flopy/modflow/mfuzf1.py
+++ b/flopy/modflow/mfuzf1.py
@@ -1005,7 +1005,7 @@ def load_util2d(name, dtype, per=None):
             load_util2d("irunbnd", np.int32)
 
         # dataset 4
-        if iuzfopt in [0, 1]:
+        if np.abs(iuzfopt) in [0, 1]:
             load_util2d("vks", np.float32)
 
         # dataset 4b
@@ -1049,7 +1049,7 @@ def load_util2d(name, dtype, per=None):
             if nuzf1 >= 0:
                 load_util2d("finf", np.float32, per=per)
 
-            if ietflg > 0:
+            if ietflg > 0 and iuzfopt > 0:
                 # dataset 11
                 line = line_parse(f.readline())
                 nuzf2 = pop_item(line, int)